2006/09/30 by L. Berthier, Ludovic Berthier, Giulio Biroli +9 · 3 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Physical and Chemical Molecular Interactions #Binary number #Dynamics (music) #Field (mathematics) #Glass properties and applications #Material Dynamics and Properties #Molecular dynamics #Monte Carlo method #Sensitivity (control systems) #Statistical ensemble #cond-mat.stat-mech
paper · pdf · doi:10.1063/1.2721554
published as J. Chem. Phys. 126, 184503 (2007) · 24 pages, 7 figs - Several discussions added (Arrhenius systems, hydrodynamic contributions, relation between susceptibilities and lengthscales, etc.)
arxiv created 2007/02/12 · openalex publication_date 2007/05/08 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study theoretically and numerically a family of multipoint dynamic susceptibilities that quantify the strength and characteristic length scales of dynamic heterogeneities in glass-forming materials. We use general theoretical arguments (fluctuation-dissipation relations and symmetries of relevant dynamical field theories) to relate the sensitivity of averaged two-time correlators to temperature and density to spontaneous fluctuations of the local dynamics. Our theoretical results are then compared to molecular dynamics simulations of the Newtonian, Brownian, and Monte Carlo dynamics of two representative glass-forming liquids, a fragile binary Lennard-Jones mixture, and a model for the strong glass-former silica. We justify in detail the claim made by Berthier et al. [Science 310, 1797 (2005)] that the temperature dependence of correlation functions allows one to extract useful information on dynamic length scales in glassy systems. We also discuss some subtle issues associated with the choice of microscopic dynamics and of statistical ensemble through conserved quantities, which are found to play an important role in determining dynamic correlations.